Premixing gas burner

ABSTRACT

Two interconnected shell members of sheet metal are formed with impressions which combine to form a plurality of mixing tubes disposed one beside the other and having upper ends. The shell members have chamber portions defining between them a distributing chamber, which extends over said mixing tubes and with which said mixing tubes communicate at their upper ends. A plurality of parallel burner tubes extend transversely to and communicate with said distributing chamber and are formed with burner ports.

United States Patent [191 Hein [ PREMIXING GAS BURNER [75] Inventor:Georg Hein,Huckeswagen,

Germany [73] Assignee: Joh Vaillant K.G., Remscheid,

Germany [22] Filed: June 22, 1972 [21] Appl. No.: 265,314

[52] US. Cl 239/553.3, 239/557, 239/566, 431/354 [51] Int. Cl B05b 1/14[58] Field of Search 431/180, 354, 355; 239/5533, 557, 565, 566, 568

FOREIGN PATENTS OR APPLICATIONS France 431/354 48 I IlHIFI'I'FFI'Ii T T3:0 1 T T32 [451 Mar. 26, 1974 591,619 8/1947 Great Britain 239/565Primary Examiner-Carroll B. Dority, Jr. Attorney, Agent, or Firm-Totem,McGeady and Stangler 5 7 ABSTRACT Two interconnected shell members ofsheet metal are formed with impressions which combine to form aplurality of mixing tubes disposed one beside the other and having upperends. The shell members have chamber portions defining between them adistributing chamber, which extends over said mixing tubes and withwhich said mixing tubes communicate at their upper ends. A plurality ofparallel burner tubes extend transversely to and communicate with saiddis tributing chamber and are formed with burner ports.

11 Claims, 6 Drawing Figures LL --I[ p i 2 PATENTEUHARZS I974 3, 799.452 sum 1 OF 2 -30 2s m l {10 52 I PATENTEDmzs um 3;799;4s2

SHEET 2 OF 2 Fig.

PREMIXING GAS BURNER This invention relates to a premixing burner forgasfired appliances, which comprises a plurality of mixing tubes whichare disposed one beside the other and are formed by impressions ininterconnected sheet metal shell members.

In a burner of this type which is known from the Printed GermanApplication 1,232,692, the mixing tubes terminate directly in the burnerports. To provide a grate burner having a substantially rectangularburner area, a plurality of such pairs of half-shells of sheet metal areconnected to a plurality of gas manifold tubes, which are disposed underthe half-shells and extend transversely thereto from a central gassupply pipe. Hence, each pair of half-shells of sheet metal form aplurality of mixing tubes and each of these mixing tubes communicateswith a different gas manifold. Each mixing tube terminates in a burnerport.

Such burner produces relatively large individual flames. The largeburner ports involve a danger of backfire. Where gases having a highburning velocity are burned, the large burner ports involve a risk ofbackfire. Besides, the heat output is not uniformly distributed over thecross-section of the burner so that problems arise regarding thegeneration of noise and the supply of secondary air. Burners are desiredwhich produce a multiplicity of small flames which are distributed asuniformly as possible throughout the crosssection of the burner andwhich may have relatively narrow burner ports so that the risk ofbackfire is minimized.

It is an object of the invention to provide for gas-fired appliances apremixing burner which has a high heat .output and produces burnerflames which are uniformly distributed over the cross-section of theburner.

In a premixing burner of the kind defined first hereinbefore, this isaccomplished in that the sheet metal shells define at the upper ends ofthe mixing tubes a distributing chamber, which extends over the mixingtubes and into which the mixing tubes open, and that a plurality ofparallel burner tubes are provided, which extend transversely to thedistributing chamber and have burner ports communicating with thedistributing chamber.

In the burner designed according to the invention, a plurality ofparallel, vertical mixing tubes are formed by simple means consisting oftwo interconnected halfshells of sheet metal. All these mixing tubescommunicate with a common horizontal distributing chamber, from whichthe burner tubes extend, which may have relatively small burner portsand ensure a uniform distribution of the flame over the cross-section ofthe burner. The risk of backfire is eliminated because the burner tubesmay have a multiplicity of small burner openings.

The burner tubes may have a vertically elongated, rectangular shape incross-section.

To secure the burner tubes to the pair of half-shells of sheet metal,the burner tubes may be formed on the underside with apertures and maybe secured on top of the distributing chamber in a straddling relation.In that case the half-shells of sheet metal may be interconnected byfolded seams in their vertical plane of contact. Laterally of theirplane of contact, the halfshells of sheet metal may be formed withapertures through which the distributing chamber communicates with theburner tubes. The distributing chamber is thus closed at its top, andits top wall acts as a baffle and ensures that the gas stream risingvertically in the mixing tubes will not produce an increased pressureand an irregular flame pattern at the burner ports disposed over themixing tubes.

Alternatively, the half-shells of sheet metal may be provided at the topof the distributing chamber with apertures in which the burner tubes areinserted. In this case, the burner tubes are desirably provided in thedistributing chamber with lateral openings through which thedistributing chamber communicates with the burner tubes. In that casethe underside of the burner tubes serves as a baffle for the gas whichrises in the mixing tubes.

The invention enables the use of the burner tubes in a number whichexceeds that of the mixing tubes. The number of mixing tubes may then beselected in view of the desired output of the burner. The number ofburner tubes is selected in view of the desired distribution of theflames over the surface of the burner.

In a particularly desirable design, a nozzle tube is provided whichcarries gas outlet nozzles disposed below the mixing tubes, verticalplug pins for centering the mixing tubes are secured to said nozzletube, and the half-shells of sheet metal are provided between adjacentmixing tubes with hemicylindrical impressions, which combine to formcylindrical guides with which the interconnected half-shells of sheetmetal are fitted on the plug pins. Besides, vertical holders may bemounted on the nozzle tube between adjacent nozzles, which holders areprovided each with a slot extending in the longitudinal direction of thenozzle tube and at their upper end with a transverse bore, theinterconnected half-shells of sheet metal may have surface portionswhich are disposed between adjacent mixing tubes and inserted into theslots in the holders, and the half-shells of sheet metal may be securedby threaded fasteners, which extend through the transverse bores andthrough apertures formed in the half-shells of sheet metal and alignedwith said transverse bores. This ar' rangement ensures a simplecentering of the mixing tubes with the nozzles on the nozzle tube. Themixing tubes may be secured by means of two screws so that the mixingtubes can easily be detached and removed, e.g., for cleaning.

In a development of the invention, the half-shells of sheet metal areprovided between two mixing tubes with a central aperture, through whicha curved gas supply pipe extends to the nozzle tube. The curved gassupply pipe supplies the gas from above into the nozzle tube so that thenozzle tube may be disposed on a lower level and the burner with itsburner tubes does not undesirably protrude upwardly so as to add to theoverall height of the appliance. In a preferred design, this supply ofgas through a curved gas supply pipe need not involve an interruption ofthe distributing chamber, which extends throughout the length of theburner.

Additional features of the invention will become apparent from theappended claims and the following illustrative embodiments withreference to the accompanying drawings, in which FIG. 1 is a fragmentaryfront elevational view showing part of a premixing burner according toone embodiment of the invention,

FIG. 1a is a cross-sectional view taken along line la-la in FIG. 1;

FIG. 2 is a side elevational view, partly in section, looking generallyin the direction of arrow II in FIG. 1,

FIG. 3 is a partial sectional view of a modified embodiment,

FIG. 4 is a front elevational view showing a preferred premixing burneraccording to a further modified embodiment of the invention, and

FIG. 5 shows an embodiment of a burner according to the invention whichis similar to that of FIG. 1.

A burner unit is shown in FIG. 2 and comprises a gas inlet connectingpipe 10, which by means of a cap nut 12 is connected to a gas valve, notshown, of a gas-fired water heater. Gas is conducted from the gas inletconnecting pipe through a downwardly curved gas supply pipe 14 to anozzle tube 16. Regularly spaced gas outlet nozzles 18 are mounted onthe nozzle tube 16. Above the nozzle tube is a mixing tube unit 26.

Two plug pins are secured to the nozzle tube 16 between adjacent nozzles18 (see FIG. 1). Each of the plug pins 20 forms a shoulder 22. Holders24 are secured to and extend upwardly from the nozzle tube 16 forattachment to the mixing tube unit 26. In the range of the mixing tubeunit 26, the holder has an upwardly extending slot 24a, note FIG. la.The holders each have a transverse bore 24b adjacent the upper end.

A mixing tube unit 26 consists of two embossed halfshells 28, 30 ofsheet metal. The half-shells have impressions 32, which combine to formparallel, vertical mixing tubes. Surface portions 34 are disposedbetween these mixing tubes. Above the mixing tubes, the halfshells 28,30 are provided with transversely extending impressions 36, 38, whichform a distributing chamber 40, which extends transversely over themixing tubes. The mixing tubes 42 formed by the impressions 32 open intothis distributing chamber 40.

Between adjacent mixing tube impressions 32, each of the half-shells ofsheet metal is formed with two hemicylindrical impressions 44, which arecombined to form a cylindrical guide. To assemble the burner, the mixingtube unit 26 is fitted on the plug pins so that the guides formed by theimpressions 44 of the mixing tube unit 26 are fitted on the plug pins 20until the lower edge of the unit 26 engages the shoulder 22. Each mixingtube 42 is then exactly centered over one nozzle 18 and is spaced fromthis nozzle 18 by a distance which is defined by the shoulder 22.

Two surface portions 34 of the half shells 28, 30, disposed betweenadjacent mixing tubes 42, are inserted into the slots 24a of the holders24. The mixing tube unit 26 is secured by two threaded fasteners 46,each of which extends through one of the transverse bores 24b in theholders 24 and through registering apertures 28a, 30a in the sheet metalhalf shells 28, 30.

A series of burner tubes 48 which are rectangular in cross-section aresecured to the mixing tube unit 26 above the distributing chamber 40.For this purpose, each of the burner tubes is provided on the undersidewith a U-shaped aperture 50 with which it straddles the distributingchamber 40. A communication between the distributing chamber 40 and theinterior of the burner tube 48 is established by two apertures 54, 56,which are formed in the half-shells of sheet metal within the burnertubes 48 and are disposed laterally of the plane of contact 52 of thehalf-shells 28, 30 of sheet metal. As a result, a wall portion 58 isleft which is disposed on the axis of the mixing tube 42 and serves as abaffle and ensures a uniform distribution of the gas pressure in theburner tube 48.

In the plane of contact 52, the half-shells 28 and 30 of sheet metal areinterconnected by a folded seam 60. As is apparent from FIG. 1, thefolded seam 60 is interrupted at the top of the distributing chamber 40by apenures 61 in which the burner tubes 48 are held.

The gas flows through the gas supply pipe 14 into the nozzle tube 16 andis discharged through the gas outlet nozzles 18. Primary air is thusentrained by injector action and is mixed with the gas in the mixingtube 42. The gas-air mixture from the several mixing tubes 42 enters thedistributing chamber 40 and from the latter flows into the burner tubes48 through the apertures 54, 56. From the burner tubes 48, the gas isdischarged through a large number of small gas discharge ports 62. Thenumber of burner tubes 48 exceeds the number of mixing tubes 42. Thearrangement according to the invention results in a uniform distributionof the individual flames throughout the surface 63 of the burner.

FIG. 3 shows a modified embodiment, in which the half-shells 28, 30 ofsheet metal are formed in their top portions with U-shaped apertures 64,in which the burner tubes 48 are inserted. A communication between thedistributing chamber 40 and the burner tubes 48 is established bylateral openings 65 in the burner tubes. In this design, the underside66 of the burner tubes serves as a baffle for the rising gas stream.

In the embodiment shown in FIG. 1 the gas supply pipe 14 is disposedbetween two burner units.

FIG. 4 shows a preferred embodiment, which in the other detailscorresponds to the embodiment shown in FIG. 1 but in which thehalf-shells 28, 30 of sheet metal have a central aperture 68, throughwhich the arcuate gas supply pipe 14 extends to the nozzle tube 16. Thedistributing chamber 40 extends throughout the width of the burner. InFIGS. 4 and 5, corresponding parts are designated with the samereference characters as in FIGS. 1 and 2.

FIG. 5 shows the complete burner of FIG. 1 and two mixing tube units 26and 27, between which the curved gas supply pipe 14 extends centrally tothe nozzle tube 16. In the embodiment shown in FIG. 5, the distributingchamber is divided into two distributing chamber sections 40 and 41.

Instead of two separate half-shells of sheet metal, half-shells of sheetmetal may be used which form an integral sheet metal element which isreversely bent through adjacent to the surface 58 in FIG. 2.

What is claimed is:

1. A premixing gas burner comprising two interconnected sheet metalshell members, each of said shell members having impressions whichcooperate therebetween to form a plurality of generally paralleldisposed mixing tubes, each of said mixing tubes having an upper end,each of said shell members having chamber portions which cooperatetherebetween to form a distributing chamber which extends across saidmixing tubes, said upper ends of said mixing tubes being incommunication with said distributing chamber, and a plurality of burnertubes extending transversely of said distributing chamber, said burnertubes being in communication with said distribution chamber and havingmeans thereon defining burner ports.

2. A premixing gas burner as set forth in claim 1, in which said burnertubes are vertically elongated and have a rectangular shape incross-section.

3. A premixing gas burner as set forth in claim 1, in which said burnertubes are secured to said chamber portions in a straddling relation andare formed on the underside with apertures through which said burnertubes communicate with said distributing chamber.

4. A premixing gas burner as set forth in claim 3, in which said shellmembers consist of half-shells contacting each other in a vertical planeof contact and interconnected by folded seams disposed in said plane ofcontact,

one of said folded seams extends at the top of said distributingchamber, and

said chamber portions comprise seat portions which are disposed on topof said distributing chamber and in which said burner tubes are seatedand which are formed with apertures which interrupt said one foldedseam.

5. A premixing gas burner as set forth in claim 3, in which saidhalfshells are formed adjacent to said distributing chamber and burnertubes with apertures which are disposed laterally of said plane ofcontact and through which said distributing chamber communicates withsaid burner tubes.

6. A premixing gas burner as set forth in claim 1, in which said chamberportions comprise apertured seat portions disposed on top of saiddistributing chamber and said burner tubes are inserted in saidapertured seat portions.

7. A premixing gas burner as set forth in claim 6, in which said burnertubes are formed with lateral apertures which are disposed within saiddistributing chamber and through which said distributing chambercommunicates with said burner tubes.

8. A premixing gas burner as set forth in claim 1, in which the numberof said burner tubes exceeds the number of said mixing tubes.

9. A premixing gas burner as set forth in claim 1, in

which each of said mixing tubes has an open lower end, said shellmembers consist of half-shells, each of which is formed with at leasttwo hemicylindrical impressions, each of which is formed between twoadjacent ones of said mixing tubes, and said hemicylindrical impressionsin said half-shells combine to form at least two transversely spacedcylindrical guides, and a nozzle tube is provided and carries upwardlydirected gas outlet nozzles axially aligned with said lower ends ofrespective ones of said mixing tubes, and two upwardly directed plugpins mounted on said nozzle tube, which are fitted into respective onesof said cylindrical guides.

10. A premixing gas burner as set forth in claim 9, in which at leasttwo vertical holders which are spaced in the longitudinal direction ofsaid nozzle tube are mounted on the latter between adjacent ones of saidnozzles, each of said holders is formed with a slot extending in thelongitudinal direction of said nozzle tube, each of said holders has anupper end portion formed with a transverse bore, said half-shellscomprise portions disposed between adjacent ones of said mixing tubesand extending through said slots in said holders, said half-shells areformed with apertures aligned with said transverse bores, and saidhalf-shells are secured to said holders by threaded fasteners extendingthrough said transverse bores and said apertures aligned therewith. 11.A premixing gas burner as set forth in claim 1, in which each of saidmixing tubes has an open lower end, a nozzle tube is provided andcarries upwardly directed gas outlet nozzles axially aligned with saidlower ends of respective ones of said mixing tubes,

said shell members are formed at the center of their length with anaperture, which. is disposed between two adjacent ones of said mixingtubes, and

a curved gas supply pipe extends through said aperture and communicateswith said nozzle tube.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION D d March 26, 1974Patent No. 3 799 452 Inventor s) Georg Hein It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In'the heading of the patent, insert -[30] Foreign Application PriorityData February 19, 1972 Germany.. .P 22 07 888.2

Signed and sealed this 30th day of July 197 Attest:

McCOY M. GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents USCOMM-DC 60370-P69 U,S. GOVERNMENT PRINTING OFFICE "'90-366-334.

FORM PO-105O (10-69)

1. A premixing gas burner comprising two interconnected sheet metalshell members, each of said shell members having impressions whichcooperate therebetween to form a plurality of generally paralleldisposed mixing tubes, each of said mixing tubes having an upper end,each of said shell members having chamber portions which cooperatetherebetween to form a distributing chamber which extends across saidmixing tubes, said upper ends of said mixing tubes being incommunication with said distributing chamber, and a plurality of burnertubes extending transversely of said distributing chamber, said burnertubes being in communication with said distribution chamber and havingmeans thereon defining burner ports.
 2. A premixing gas burner as setforth in claim 1, in which said burner tubes are vertically elongatedand have a rectangular shape in cross-section.
 3. A premixing gas burneras set forth in claim 1, in which said burner tubes are secured to saidchamber portions in a straddling relation and are formed on theunderside with apertures through which said burner tubes communicatewith said distributing chamber.
 4. A premixing gas burner as set forthin claim 3, in which said shell members consist of half-shellscontacting each other in a vertical plane of contact and interconnectedby folded seams disposed in said plane of contact, one of said foldedseams extends at the top of said distributing chamber, and said chamberportions comprise seat portions which are disposed on top of saiddistributing chamber and in which said burner tubes are seated and whichare formed with apertures which interrupt said one folded seam.
 5. Apremixing gas burner as set forth in claim 3, in which said half-shellsare formed adjacent to said distributing chamber and burner tubes withapertures which are disposed laterally of said plane of contact andthrough which said distributing chamber communicates with said burnertubes.
 6. A premixing gas burner as set forth in claim 1, in which saidchamber portions comprise apertured seat portions disposed on top ofsaid distributing chamber and said burner tubes are insertEd in saidapertured seat portions.
 7. A premixing gas burner as set forth in claim6, in which said burner tubes are formed with lateral apertures whichare disposed within said distributing chamber and through which saiddistributing chamber communicates with said burner tubes.
 8. A premixinggas burner as set forth in claim 1, in which the number of said burnertubes exceeds the number of said mixing tubes.
 9. A premixing gas burneras set forth in claim 1, in which each of said mixing tubes has an openlower end, said shell members consist of half-shells, each of which isformed with at least two hemicylindrical impressions, each of which isformed between two adjacent ones of said mixing tubes, and saidhemicylindrical impressions in said half-shells combine to form at leasttwo transversely spaced cylindrical guides, and a nozzle tube isprovided and carries upwardly directed gas outlet nozzles axiallyaligned with said lower ends of respective ones of said mixing tubes,and two upwardly directed plug pins mounted on said nozzle tube, whichare fitted into respective ones of said cylindrical guides.
 10. Apremixing gas burner as set forth in claim 9, in which at least twovertical holders which are spaced in the longitudinal direction of saidnozzle tube are mounted on the latter between adjacent ones of saidnozzles, each of said holders is formed with a slot extending in thelongitudinal direction of said nozzle tube, each of said holders has anupper end portion formed with a transverse bore, said half-shellscomprise portions disposed between adjacent ones of said mixing tubesand extending through said slots in said holders, said half-shells areformed with apertures aligned with said transverse bores, and saidhalf-shells are secured to said holders by threaded fasteners extendingthrough said transverse bores and said apertures aligned therewith. 11.A premixing gas burner as set forth in claim 1, in which each of saidmixing tubes has an open lower end, a nozzle tube is provided andcarries upwardly directed gas outlet nozzles axially aligned with saidlower ends of respective ones of said mixing tubes, said shell membersare formed at the center of their length with an aperture, which isdisposed between two adjacent ones of said mixing tubes, and a curvedgas supply pipe extends through said aperture and communicates with saidnozzle tube.